Inlet device for pneumatic transport conduit



Dec. 31, 1957 J. LANG ETAL 0 INLET DEVICE FOR PNEUMATIC TRANSPORT CONDUIT Filed March 18 1955 United States Patent INLET DEVICE FOR PNEUMATIC TRANSPORT CONDUIT Jules Lang and Emil Widmer, Uzwil, Switzerland, assignors to Gebrueder Buehler, Uzwil, Switzerland Application March 18, 1955, Serial No. 495,234

Claims priority, application Switzerland March 25, 1954 Claims. (Cl. 302-57) This invention relates to a feeding device for pneumatically operable transport ducts.

In these pneumatic transport ducts and conduits obstructions often occur which close up and choke the ducts; consequently, the conveying air cannot flow through the ducts and the transport of goods is accordingly interrupted.

In order to eliminate these disturbances so-called flushing flaps are being provided at suitable places of the transport installations which permit cleaning air to enter the ducts.

The invention is based on the recognition that the working simplicity and the reliability of the transport ducts can be improved without the application of these flushing flaps.

Experience has proven that the obstructions particularly happen if the goods are conducted into the transport ducts at an insufiicient air speed which causes the goods to settle at different places of the transport installation. This insufiicient air speed mainly results when the air flow at the entrance into the ducts is throttled by the goods.

It is the main object of the invention to eliminate the above recited disadvantages and to provide means whereby any interruption of the air flow through the pneumatic transport ducts is prevented.

With this purpose in view the intake part of the duct is divided by a partition into two superposed channels, the upper channel being used to feed the goods into a pneumatic duct and the lower channel serving to secure the necessary minimum quantum of conveying air, the length of the partition extending into the transport duct as well as the space relationship of the channels are so chosen that if the air quantity diminishes the feeding of the goods stops before the conveying speed has dropped beneath a safe working value.

The invention is by way of example illustrated in the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional view along the middle plane of a feeding device for pneumatic transport ducts;

Fig. 2 is a vertical sectional view along A to A of Fig. 1; i

Fig. 3 is a schematical view of the application of the invention to a roller mill; and

Fig. 4 is a schematic view of its application to a bin outlet.

The goods contained in the hopper 1 (Fig. 1) flow into the duct 3 through passage 5 of the inlet box 2. A partition 4 divides inlet box 2 and the inlet end of the transport duct 3 into an upper portion or channel 5, 6 for the feed of the goods and a lower channel 7, 8 for the admission of cleaning air. The partition 4 preferably extends into the transport duct 3 for a length that is greater than one and one-half of the diameter of the transport duct 3. This length is measured from the separation device 9 between inlet box 2 and transport duct 3. The length and the sectional relationship of the channels 5, 6 and 7, 8 are controlled by the nature of the goods and the diameter of the transport duct. The cross sectional relationship of the two channels lies preferably between 1:2 and 2:1.

In an inlet device which, for instance, is mounted to a roller' mill (Fig. 3), a large part of the conveying air enters in normal work with the charge through hopper 1 and channel 5, 6. Furthermore, through a pipe 10, which is placed in the hopper 1 and has its intake placed over the highest level of the goods, and through channel 7, 8 clean air enters into transport duct 3.

In an inlet device which, for instance, is attached to a bin outlet (Fig. 4), almost no air passes with the goods through channel 5, 6; the whole conveying air quantity must enter transport duct 3 through an intake 11 and through channel 8.

If the quantity of air diminishes and the conveying speed drops underneath a safe value, the goods remain in the part of the partition 4 which extends into the transport duct 3 and do not fall into the same, which could clog the aperture 12 of channel 8. When a satisfactory air supply is restored deposits at any place of the transport duct are flushed by the air entering through aperture 12 and the feeding of the goods into transport duct 3 is resumed.

To adapt the inlet device to the characteristics of the charge the length of partition 4 and the cross sectional relationship of channels 6 and 8 can be regulated from the outside during the operation of the device and the air quantity in channel 8 can be regulated by a throttle member.

In the embodiment represented by Fig. 1 and Fig. 2, a plate 13 located directly under partition 4 is secured by longitudinal strips 14. Its position is controlled by a rod 17 and nuts 16, which permit during the operation to regulate from outside the prolongation 15 of that part of partition 4 which extends into transport duct 3. The prolongation 15 is considered to make up the length of the partition 4.

Plate 13 is resilient and presses against a screw 18. By turning screw 18 it is possible to regulate from outside during the operation of the cross-sectional relation ship of channels 6 and 8. A plate 19 which functions as slide valve effects a throttling of the air in channel 7, 8.

Since certain changes may be made in the above invention and different embodiments of the same could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific exemplification of the invention described therein.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:

1. In a pneumatically suction-operated tubular transport duct an intake for the materials to be transported at the one end of said duct and an outlet at opposite end, a partition in said intake to divide the same into two vertically superposed channels, the upper channel being adapted to feed said materials into said duct and the lower channel adapted to secure the required amount of conveying air, said partition extending into said conveyor duct for a distance which exceeds one and onehalf of the duct diameter.

2. In a transport duct according to claim 1, a plate located underneath the lower end-piece of said partition and length-extending beyond the same and means located outside of said transport duct to create a longitudinal displacement of said plate.

3. In a transport duct according to claim 1, a sub stantially vertical'tube'attached to said partition to lead air into .said lower 1 channel and reaching into a vgoods container, the upper end of said tube being placed above the highest level of the goods.

4. In cattransport ::duct .according to :claim ,1, .-a bin zfeeding into said transport duct .and :an intake to dead air into said lower channel, said intake ;being :placed toutsiclesaid bin.

5. .In atransport duct according toeclaim ,1, a:contro1 References Cited'in the file of this patent "UNITED STATES PATENTS Palmer Apr. 19, 1881 McConnell June 28, 1892 Worsharn Dec. 26, 1916 Wallace, Apr. 28, 1925 FOREIGN PATENTS Switzerland Oct. 7, 1930 -G.ermany Oct. 1, 1953 

